PROVIDENCE, RI — Fish tends to have a reputation for being one of the healthiest foods you can eat, but a new study reveals that too much may actually increase your risk of developing skin cancer. Researchers at Brown University have found that consuming more fish significantly increases the risk of malignant melanoma, the deadliest form of skin cancer.
As for, the team found that fried fish wasn’t the biggest culprit here. In fact, eating more tuna and unfried fish has helped increase cancer risk.
“Melanoma is the fifth most common cancer in the United States, and the lifetime risk of developing melanoma is one in 38 for whites, one in 1,000 for blacks, and one in 167 for Hispanics. Although fish consumption has increased in the United States and Europe in recent decades, results from previous studies investigating associations between fish consumption and melanoma risk have been inconsistent. Our results have identified an association that requires further investigation,” corresponding author Eunyoung Cho said in a press release.
Less than one fish a day increases cancer risk
Researchers looked at the fish consumption and melanoma risk of more than 490,000 adults across the United States, with an average age of 62. These people all participated in the NIH-AARP Diet and Health Study between 1995 and 1996, reporting how often they ate french fries. fish, unfried fish, tuna and their portion sizes over the past year. The study then followed these adults for another 15 years, keeping track of how many people developed skin cancer.
During the study, 5,034 participants (1.0%) developed malignant melanoma and 3,284 (0.7%) developed “stage 0 melanoma” – abnormal cells on the outer layer of their skin uniquely.
Compared to adults eating about three grams of fish per day, people consuming more than 42 grams per day had a 22% higher risk of developing malignant melanoma. Participants consuming an average of 42.8 grams of fish per day also had a 28% higher risk of developing stage 0 melanoma.
For reference, a standard serving of fish equals about 140 grams of cooked fish, which means eating just one-third of a fish dinner each day can significantly increase the risk of melanoma.
Fish doesn’t need to be fried to increase cancer risk
Specifically, the team found that people consuming an average of around 14 grams of tuna a day had a 20% higher risk of malignant melanoma than those consuming an average of just 0.3 grams a day. Similarly, those who ate 17.8 grams of unfried fish per day had an 18% higher risk of developing melanoma and a 25% higher risk of stage 0 melanoma.
Interestingly, researchers did not find a strong link between fried fish consumption and higher cancer risks. So what is causing this potential link to cancer?
“We believe that our findings could possibly be attributed to contaminants in fish, such as polychlorinated biphenyls, dioxins, arsenic and mercury. Previous research has shown that high fish consumption is associated with higher levels of these contaminants in the body and identified associations between these contaminants and a higher risk of skin cancer.However, we note that our study did not investigate the levels of these contaminants in the participants’ bodies and therefore further research is needed to confirm this relationship,” Cho said.
The study authors note that their findings are observational only, meaning they cannot definitively link eating more fish to more cases of skin cancer. The study also did not take into account other factors that contribute to melanoma, including the number of moles, hair color, history of sunburn and other sun-related habits.
However, they took into account each participant’s body mass index (BMI), physical activity, smoking history, alcohol consumption and family history of cancer.
The study is published in the journal Cancer causes and control.